1. Field of the Invention
The invention relates to woven slide fasteners and to methods and apparatus for weaving slide fastener chains.
2. Description of the Prior Art
The prior art contains many woven slide fastener chains as well as methods and apparatus for the manufacture thereof; such a weaving apparatus being disclosed in U.S. Pat. No. 3,123,103. In the prior art a continuous coupling element is fed in synchronism with warp threads to a weaving station where a weft thread is woven with the warp threads and passed over interconnecting portions of the continuous coupling element to form a stringer of a slide fastener chain. Although stringers with various types of continuous coupling elements, such as spiral coupling elements, meander coupling elements, continuous trains of molded coupling elements, etc., have been woven to the edges of tapes, most woven slide fasteners are made with spiral coupling elements rather than with meander or other types of coupling elements in spite of the fact that the crosswise strength of slide fasteners with spiral coupling elements, which are formed from a filament of oblate cross-section twisted in a manner to produce interlocking head portions, is less than the crosswise strength of similar size meander filament type interlocking coupling elements which have enlarged interlocking head portions formed by plastic deformation of the filament. Sometimes longitudinal cords have been included within the coils of spiral coupling elements in the woven stringers. The commercially acceptable slide fasteners employing meander coupling elements are generally made by sewing the leg portions of the meander coupling elements to the tape rather than weaving the meander coupling element with the tape; prior art woven slide fasteners with meander coupling elements generally are deficient in that the meander coupling elements were not sufficiently secured to maintain adequate stability and positioning of the meander coupling elements.